Case for defibrillator electrode pads and release liner

ABSTRACT

A case for defibrillator electrode pads on a release liner is described which protects the pads prior to use and retains them in either an electrically connected or electrically disconnected configuration. When the case is closed, spring contacts on opposite sides of the inside of the case retain the pads and release liner in place. The retention either holds electrical conductors in contact with each other to retain the pads in electrical connection with each other, or in a different configuration in which the pads are not electrically connected.

This invention relates to defibrillators for cardiac resuscitation and,in particular, to electrode pads for defibrillators.

Cardiac arrest is a life-threatening medical condition in which thepatient's heart fails to provide blood flow to support life. Adefibrillator can be used to deliver defibrillating shocks to a patientsuffering from cardiac arrest. The defibrillator resolves this conditionby delivering a high-voltage impulse to the heart in order to restorenormal rhythm and contractile function in patients who are experiencingarrhythmia such as VF (ventricular fibrillation) or VT (ventriculartachycardia) that is not accompanied by spontaneous circulation. Thereare several classes of defibrillators, including manual defibrillators,implantable defibrillators, and automatic external defibrillators(AEDs). AEDs differ from manual defibrillators in that AEDs canautomatically analyze the electrocardiogram (ECG) rhythm to determine ifdefibrillation is necessary. The defibrillator analyzes the ECG signalfor signs of arrhythmia. If VF is detected, the defibrillator signalsthe rescuer that a shock is advised. After the detection of VF or othershockable rhythm, the rescuer presses a shock button on thedefibrillator to deliver a defibrillation pulse to resuscitate thepatient.

External defibrillators act through electrode pads applied across thechest of the patient. The electrodes adhesively attach to the patientand are used both to acquire an ECG signal from the patient's heart andto apply the defibrillating shock. AED electrodes commonly are formed bylocating a foil or metallized electrode between a flexible nonconductivebacking and a conductive adhesive gel. The conductive adhesive attachesthe electrode securely to the patient. Gels, however, will dry out(desiccate) over time and have a finite shelf life. A typical shelf lifefor an electrode with gel adhesive is about two years, after which theelectrodes must be replaced. Some AEDs use electrodes which are simplyreplaced when the safe shelf life period has expired. Other AEDs have aninternal self-test circuit which periodically tests the electrodes anddetects desiccation by an impedance change. For self-test electrodes theelectrodes are electrically connected to each other to form a continuousclosed loop circuit that is tested. The closed loop circuit is brokenwhen the electrode pads are deployed for use.

In the case of both self-tested electrodes and non-self-testedelectrodes, it is typical that the electrodes will be connected to theAED while stored prior to use so that the rescuer does not need toconnect them; they are already pre-connected and ready for use. Theself-test electrodes are pre-connected with the loop circuit closed forself-testing. The non-self-test electrodes are generally not connectedin a closed loop circuit while stored prior to use. Hence, two differentstyles of electrodes are needed for self-testing and non-self-testingdefibrillators.

Our concurrently filed U.S. patent application 60/865,482 describes arelease liner for a pair of electrodes with a moisture-impermeablesurface on which the electrodes are peripherally attached, sealing theconductive gel of the electrodes between the moisture-impermeablebacking of the electrodes and the moisture-impermeable surface of therelease liner. The release liner also has an electrical contactelectrically connected to each electrode. When the release liner isfolded in a first configuration the electrical contacts are brought intocontact with each other, completing an electrical connection between thetwo electrodes. When the release liner is not in this configurationthere is no electrical connection between the two electrodes. It wouldbe desirable to have a device which both retains the release liner andelectrodes in the desired configuration and protects the release linerand electrodes prior to use.

In accordance with the principles of the present invention, a releaseliner for defibrillator electrode pads is described which can be usedfor electrode pads connected in a closed loop for self-test and forelectrode pads connected in an open circuit. The release liner includestwo areas where electrode pads are attached prior to use. When theelectrodes are attached to the release liner the adhesive gel of eachelectrode is electrically connected to a conductor that provides theclosed circuit for self-test electrodes. When the release liner isfolded one way a closed circuit is completed between the electrodes.When not folded this way there is no closed circuit between theelectrodes. In one embodiment described below a clip is provided toretain the folded release liner in either the closed circuit or opencircuit configuration. In another embodiment a case is provided with aninternal clip that retains the release liner and electrodes in thedesired configuration. The case also protects the electrodes prior touse.

In the drawings:

FIG. 1 illustrates a halibut-style release liner and electrodesconstructed in accordance with the principles of the present invention.

FIG. 2 a illustrates a first example of a release liner of the presentinvention in an exploded view.

FIG. 2 b is a plan view of the release liner of FIG. 2 a after assembly.

FIG. 3 illustrates a halibut-style release liner and electrodesconnected to a defibrillator.

FIG. 4 illustrates a halibut-style release liner and electrodesconnected to an AED.

FIG. 5 a is a perspective view of a case for a release liner andelectrode of the present invention and FIG. 5 b is a cross-sectionalview of the case of FIG. 5 a.

FIG. 6 a illustrates a second example of a release liner of the presentinvention in an exploded view.

FIG. 6 b is a plan view of the release liner of FIG. 6 a after assemblyand configured for a closed circuit connection to a defibrillator.

FIG. 7 a illustrates the second example of a release liner of thepresent invention in an exploded view.

FIG. 7 b is a plan view of the release liner of FIG. 7 a after assemblyand configured for an open circuit connection to a defibrillator.

FIG. 8 a is a plan view of a halibut release liner which is folded toelectrically connect the electrodes and uses a single release linersheet.

FIG. 8 b is a plan view of a halibut release liner which is punched orcut to electrically disconnect the electrodes and uses a single releaseliner sheet.

Referring first to FIG. 1, a halibut-style release liner 30 andelectrode set 10,20 is shown in plan view. The style is referred to ashalibut-style herein by reason of the resemblance of the relativelyflat, flexible electrodes 10,20 to the fish of the same name whenattached to the release liner. In this view the nonconductive backingsurface of the electrodes 10,20 is facing the viewer. The adhesive gelon the other side is in contact with the release surface 42 of therelease liner 30. A wire 18,28 is connected through the backing of eachelectrode 10,20 to the inner conductive layer of the electrode and isheld in place by a fastener such as a rivet 16,26. Desiccation of thegel is retarded by sealing the nonconductive backing of each electrodeto the moisture impermeable release surface 42 of the release liner. Theseals 14, 24 are made around the periphery of the gel areas of theelectrodes. A tab 12, 22 is formed at the end of the backing of theelectrodes and may be grasped by a user to pull the electrodes away fromthe release liner when they are to be used.

Located inside the release liner 30 under each electrode 10,20 is aconductive sheet 44 (see FIG. 2) of metallic foil or other thinconductive material. The lateral extent of each sheet is indicated bydashed lines 32 a,32 b and 34 a,34 b. A hole 36, 38 is formed in theouter release surface layer 42 to give access to each conductive sheet.It is seen that each side of the halibut release liner of FIG. 1 is amirror image of the other about the center fold line 40 of the releaseliner 30. In accordance with the principles of the present invention,when the two sides are folded up and toward each other, the hole 36 willbe opposite the hole 38 so that the conductive sheets visible throughthe holes can be brought into electrical contact with each other. Whenthe release liner remains flat as shown in the drawing or when foldedback along the fold line 40 so that the back sides (not visible inFIG. 1) are brought into contact with each other, there is no contact orelectrical connection of the sheets within the release liner.

FIGS. 2 a and 2 b illustrate how the manner in which the release lineris folded dictates whether an open circuit or closed circuit is formedwith the electrodes. In the exploded view of FIG. 2 a, the nonconductiverelease surface layer 42 is seen to have four holes in it, the twopreviously described access holes 36,38 for the inner conductive sheets44 and two holes 48 a and 48 b which underlie the electrodes when theyare sealed to the layer 42.

The bottom layer of the release liner is a nonconductive layer 46.Between the layers 42 and 46 are the two conductive sheets 44 whichunderlie the electrode positions and holes 36,38 on each side of therelease liner. When the conductive sheets are sealed between layers 42and 46 their lateral sides in this example are positioned as shown bydashed lines 32 a,32 b for the left side conductive sheet and dashedlines 34 a,34 b for the right side conductive sheet as shown in FIG. 2b. Referring to FIG. 1 and FIG. 2 b, it is apparent how the electrodes10,20 can be electrically connected together. When the release liner isfolded along fold line 40 so that the left and right upper sides arebrought into contact with each other, an electrical circuit is completedbetween the wire 18 of the left electrode 10, the conductive layer ofthat electrode, its gel layer which is in contact with the leftconductive sheet 44 of the release liner through the hole 48 a, throughholes 36 and 38 and the contact between the left and right conductivesheets 44 through those holes, from the right conductive sheet to thegel of the right electrode 20 through hole 48 b, to the conductive layerof the electrode 20 and to its wire 28. When the two wires 18,28 areconnected to a defibrillator a closed loop circuit is thus formed withthe defibrillator. To keep the left and right conductive sheets 44 inelectrical contact with each other when the release liner is foldedclosed in this configuration, a clip 150 or other fastening device maybe applied to pinch the two conductive sheets 44 into contact with eachother through holes 36 and 38 as shown in FIG. 2 b. Other alternativeholding techniques may be used such as fastening the sheets with aconductive adhesive when holes 36 and 38 are brought into contact witheach other. In this closed loop circuit configuration the electrodes maybe readily self-tested by signals applied by the defibrillator to whichwires 18 and 28 are connected.

When the release liner and electrode are to be connected to adefibrillator which does not require closed loop connection of theelectrodes it is sufficient that the conductive sheets visible throughthe holes 36 and 38 not be brought into contact with each other. Therelease liner can be folded the opposite way with the back sides of therelease liner (layer 46) in contact with each other. If desired the clip150 can be used to retain the release liner in this foldedconfiguration. The release liner can alternatively be left unfolded asit is in FIGS. 1 and 2 b.

Variations of this example will be readily apparent to those skilled inthe art. For instance the conductive sheets 44 do not need to have theshape illustrated in this example; they can simply be conductors betweenthe electrode hole 48 a and the access hole 36 and between electrodehole 48 b and access hole 38. One of the electrodes could be located onthe other side (the layer 46 side) of the release liner provided thatthe electrode hole for that electrode were on that side of the releaseliner. The holes 36,38 could be punched through the release layer 42 butthe punched material not removed unless the closed loop configurationwere to be employed. Separate insulating covers could be used over oneor both of the holes 36,38 to prevent electrical connection between thetwo conductive sheets 44 even in the forward folded condition. Othervariations are also possible.

FIG. 3 shows the halibut release liner and electrodes when connected toa defibrillator 310. An ECG front end circuit 202 is connected to thewires 18,28 of the electrodes 10,20. In FIG. 3 the electrodes 10,20 areshown peripherally attached to the two sides 30 a,30 b of the releaseliner 30 prior to being peeled off of the release liner and attached tothe patient. The ECG front end circuit 202 operates to amplify, buffer,filter and digitize an electrical ECG signal generated by the patient'sheart and picked up by the electrodes to produce a stream of digitizedECG samples. The digitized ECG samples are provided to a controller 206that performs an analysis to detect VF, shockable VT or other shockablerhythm. If a shockable rhythm is detected, the controller 206 sends asignal to HV (high voltage) delivery circuit 208 to charge a highvoltage capacitor of circuit 208 in preparation for delivering a shock,and a shock button on a user interface 214 is activated to beginflashing. The rescuer 220 is then advised by an audible instruction tokeep away from the patient (“hands off” instruction). When the rescuerpresses the shock button on the user interface 214 a defibrillationshock is delivered from the HV delivery circuit 208 to the patientthrough the electrodes 10,20.

The controller 206 is coupled to further receive input from a microphone212 to produce a voice strip. The analog audio signal from themicrophone 212 is preferably digitized to produce a stream of digitizedaudio samples which may be stored as part of an event summary 134 in amemory 218. The user interface 214 may consist of a display, an audiospeaker, and control buttons such as an on-off button and a shock buttonfor providing user control as well as visual and audible prompts. A userinterface of the present invention may also include one or more controlbuttons for selecting a rescue protocol stored in memory 218 to becarried out during a rescue. A clock 216 provides real-time or elapsedtime clock data to the controller 206 for time-stamping informationcontained in the event summary 134. The memory 218, implemented eitheras on-board RAM, a removable memory card, or a combination of differentmemory technologies, operates to store the event summary 134 digitallyas it is compiled during the treatment of the patient 210. The eventsummary 134 may include the streams of digitized ECG, audio samples, andother event data as previously described.

FIG. 4 illustrates halibut electrodes of the present invention coupledto a defibrillator 310. The defibrillator 310 represents asemi-automatic external defibrillator (AED). However, other types ofexternal defibrillators can be used as well. The AED 310 is housed in arugged polymeric case 312 which protects the electronic circuitry insidethe case, which was previously described with reference to FIG. 3, andalso protects the rescuer from shocks. Attached to the case 312 byelectrical leads 18,28 are a pair of halibut electrodes 10,20 attachedto the two sides 30 a,30 b of a release liner 30. Prior to use theelectrode pads 10,20 are retained in a cartridge 314 located in a recesson the top side of the AED 310. The electrode pads are accessed for useby pulling up on a handle 317 which allows removal of a plastic coverover the electrodes 10,20. The user interface is on the right side ofthe AED 310. A small ready light 318 informs the rescuer of thereadiness of the AED 310. In this embodiment the ready light blinksafter the AED 310 has been properly set up and is ready for use. Theready light is on constantly when the AED 310 is in use, and the readylight is off or flashes in an alerting color when the AED 310 needsattention.

Below the ready light is an on/off button 320. The on/off button ispressed to turn on the AED 310 for use. To turn off the AED 310 therescuer holds the on/off button down for one second or more. Aninformation button 322 flashes when information is available for therescuer. The rescuer depresses the information button to access theavailable information. A caution light 324 blinks when the AED 310 isacquiring heartbeat information from the patient and lights continuouslywhen a shock is advised, alerting the rescuer and others that no oneshould be touching the patient during these times. A shock button 326 isdepressed to deliver a shock after the AED 310 informs the rescuer thata shock is advised. An infrared port 328 on the side of the AED 310 isused to transfer data between the AED 310 and a computer. This data portfinds used after the patient has been rescued and a physician desires tohave the AED 310 event data downloaded to his or her computer fordetailed analysis. A speaker 313 provides voice instructions to therescuer to guide the rescuer through the use of the AED 310 to treat thepatient. A beeper 330 is provided which “chirps” when the AED 310 needsattention such as electrode pad replacement or a new battery.

FIGS. 5 a and 5 b illustrate a case or cartridge 50 for storing halibutelectrode pads prior to use in accordance with the principles of thepresent invention. The case 50 in this example is similar to thefamiliar cases which retain DVDs and can be made of a polymericmaterial, for instance. The two halves of the case 52 a,52 b are hingedtogether at one side by a hinge 54 and can be opened by depressing anindentation 56 on the other side of the case. While the case can be madeto seal airtight as by the use of a gasket where the two halves cometogether or can be shrink-wrap sealed, this is not necessary as theperipheral sealing of the electrode pads 10,20 to a release liner 30 ofpolymeric or other moisture impermeable material will provide thenecessary hermetic sealing of the electrode gel prior to use. A torsoillustration 58 on the case illustrates the proper attachment of theelectrodes to the patient.

The cross-sectional view of FIG. 5 b shows that there is a spring clip60 or other fastening device located inside the case. The two halves62,64 of the spring clip are forced together when the case is closed,clamping the release liner 30 between them at the location of the holes36,38. When the release liner is folded so that the two holes 36,38oppose each other, this clamping action maintains contact of the twoconductive sheets 44 of the release liner, completing the closedelectrical circuit between the two electrode pads for self-test by adefibrillator attached to the electrical wires or leads 18,28. The casecan also be used if the electrodes are not to be electrically connectedby folding the release liner so that the holes are on the outside facingaway from each other, in which case the clip 60 functions to retain thehalibut electrodes and release liner in the case with no electricalconnection between them. Thus, the same case 50 and halibut electrodes10,20 and release liner 30 can be used for defibrillators which requireand do not require electrical connection between the electrodes, simplyby the way in which the release liner is folded inside the case.

FIGS. 6 a and 6 b illustrate another example of a release liner forhalibut electrodes of the present invention. In the exploded view ofFIG. 6 a the nonconductive release surface layer 142 of the releaseliner is seen to have only two holes, the holes 48 a and 48 b whichunderlie the electrodes when they are sealed to the layer 142 and permitelectrical contact to an inner conductive sheet located between theouter nonconductive layers 142 and 46. The inner conductive sheet iscomposed of two sides 144 and 144′ which underlie the holes 48 a and 48b which are joined by a bridging portion 146. Thus the conductive sheetforms a continuous electrical connection between the two electrodes whenthey are attached to the release liner, as is evident from the plan viewof the assembled release liner 130 of FIG. 6 b. When the electrodes areattached to the surface 142 of the release liner 130 they areelectrically connected to each other and ready for use with adefibrillator which requires electrically interconnected electrodes.

The release liner configuration of FIGS. 6 a and 6 b can be converted toone in which the attached electrodes are not electrically interconnectedas shown in FIGS. 7 a and 7 b. This is done by breaking the electricalconnection between the two sides of the release liner 130. In theexample of FIG. 7 b this is done by punching a hole 160 through therelease liner which severs the bridging portion 146 between the twohalves 144 and 144′ of the inner conductive sheet. The two halves 144and 144′ of the conductive sheet are thus no longer electricallyconnected to each other. Unlike the embodiment of FIGS. 1, 2 a and 2 b,the electrical interconnection or lack thereof is not determined by themanner in which the release liner is folded; it is determined by whetherthe two halves of the conductive sheet remain connected or aredisconnected. The example of FIGS. 6 a, 6 b, 7 a and 7 b can be foldedor unfolded in either configuration. Also unlike the earlier embodiment,the severing of the two halves of the conductive sheet make thenon-interconnected configuration permanent, absent means to reconnectthe two halves of the conductive sheet. Another way to view the twoembodiments is that the two halves of the conductive sheet are nominallynot connected in the FIGS. 1, 2 a, 2 b embodiment and nominallyelectrically connected in the FIGS. 6 a, 6 b, 7 a, 7 b embodiment.Breaking the electrical connection of the latter changes theconfiguration to use defibrillators requiring non-connected electrodes.For example, at the end of the manufacturing process the two halves ofthe conductive sheet can be left connected and the halibut electrodesused with defibrillators requiring electrically connected electrodes, orthe bridging portion 146 can be cut and the halibut electrodes used withdefibrillators requiring electrically disconnected electrodes. The sameelectrode manufacturing line can thus make electrodes for both types ofdefibrillators.

FIG. 8 a is another example of a halibut release liner of the presentinvention. In this example the release liner comprises a single sheet830 of moisture impermeable material to which electrodes are attached asabove with the conductive gel facing the sheet. When the electrodes areperipherally sealed to the release liner sheet 830 the conductive gel ofthe electrodes is sealed as before between the moisture impermeablebacking of the electrode and the moisture impermeable release linersheet 830, protecting the gel from desiccation. Dashed lines 810 and 820indicate the areas of the release liner where the electrodes are to beattached. The release liner sheet 830 may be formed of a polymeric orplastic material or other material that is nonconductive. Conductors 832and 834 formed of thin foil, metallized ink, or other thin conductor islaminated or printed on the sheet with a portion of each positioned tocontact the electrically conductive (gel) surface of the electrode andanother portion extending outside of the attachment areas of theelectrodes. In this example the conductors each have one rounded end831,837 which makes contact with the conductive gel of an attachedelectrode and another rounded end 833,835 outside of the attachmentareas 810,820. In this example the conductors 832,834 are laminated orprinted on the side of the sheet 830 where the electrodes are to beattached, but they could also be located on the opposite side of thesheet 830 and make electrical contact through holes in the sheet. Theconductors could also be embedded or molded into the sheet 830. Theelectrodes can be attached on the same side or on opposite sides of thesheet 830.

When the electrodes are attached in the electrode attachment areas 810and 820, each attached electrode will be in electrical contact with arespective one of the conductors 832 and 834. When the sheet 840 isfolded along fold line 840 so that conductor ends 833 and 835 arebrought into contact with each other, the electrodes will beelectrically connected to each other for a defibrillator which requireselectrically connected electrodes for self-test. But when the sheet isfolded the other way or left unfolded so that there is no electricalcontact between conductors 832 and 834, the electrodes and release linerare suitable for connection to a defibrillator which does not require orcannot have preconnected electrodes electrically connected to eachother.

The release liner sheet 830 can be opaque, translucent, or transparent.A transparent sheet will enable a user to visually inspect theconductive gel of the electrodes through the sheet 830 while theelectrodes are attached to the release liner to discern anydeterioration of the gel. The gel may contain a substance or materialwhich changes color or otherwise changes visually when the moisturecontent of the gel changes, providing a quick and easy means fordetermining whether the electrodes are suitable for use.

FIG. 8 b is another example of the present invention which, as in theexample of FIG. 8 a, uses a single release liner sheet 830. Instead ofseparate conductors, a conductor 838 is laminated to, printed on, orembedded in the sheet 830 and extends between the attachment position810 for one electrode and the attachment position 820 for the otherelectrode. As before, the conductor 838 is preferably on the same sideof the sheet 830 to which the electrodes are attached, but could also beon the other side and extend through the sheet to the two electrodes.When electrodes are attached to the release liner sheet 830 in thepositions shown, the electrodes are electrically connected to each otherby the conductor 838. If the conductor 838 is broken such as by punchinga hole 860 through the conductor or through the conductor and therelease liner sheet, the attached electrodes are rendered electricallydisconnected with each other.

Other variations will readily occur to those skilled in the art. Forinstance, the conductors for the example of FIG. 8 a could simplycomprise small conductors at the locations and of the size of ends 831and 837 with holes in sheet 830 behind the conductors providing accessto conductors 831 and 837 on the back of sheet 830. When the releaseliner sheet 830 is folded back-to-back, the conductors 831 and 837 canbe brought into contact with each other through the holes in the sheet830 and clamped or attached into continuous contact to electricallyconnect the two electrodes. Folding the sheet the opposite way orleaving the sheet unfolded would leave the electrodes electricallydisconnected with each other. Other variations of the examples describedabove are also possible.

The clip 150 of FIG. 2 b can be used to retain the release liner of FIG.8 a in its desired folded configuration, either with the two electrodeselectrically connected or folded with the two electrodes electricallyseparated. Likewise the case of FIGS. 5 a and 5 b can be used to protectand retain the release liner of FIG. 8 a in either folded configuration.For the variation described in the previous paragraph which only hassmall conductors 831,837 located under the electrodes and accessible atthe back of the release liner 830 through holes in the release linersheet, the spring clip 60 or other retention device inside the case willbe aligned with the conductors 831,837 so that the desired electricalcontact through the holes of the release liner sheet is maintained bycontact of the conductors 831 and 837.

1. A release liner for electrodes which may be selectively configured toelectrically connect electrodes attached to the release linercomprising: an outer nonconductive surface to which electrodes may beattached; a conductive layer in electrical contact with each attachedelectrode and nominally electrically disconnected with each other; andan access to the conductive layer of each attached electrode; and anattachment device which can be applied to the release liner when therelease liner is folded with the accesses to the conductive layers inalignment, wherein the release liner may be folded one way and theattachment device applied to bring the conductive layer of each attachedelectrode into electrical connection, or folded another way to leave theconductive layer of each attached electrode in electrical disconnection.2. The release liner of claim 1, wherein the attachment device comprisesa clamping device.
 3. The release liner of claim 1, wherein theattachment device comprises a conductive adhesive.
 4. The release linerof claim 1, wherein the access comprises a hole through the outernonconductive surface.
 5. The release liner of claim 1, furthercomprising a second outer nonconductive surface, wherein the conductivelayer is sandwiched between the first and second nonconductive surfaces.6. The release liner of claim 5, wherein the conductive layer furthercomprises first and second inner conductive layers.
 7. The release linerof claim 1, wherein the nonconductive surface is impermeable tomoisture.
 8. The release liner of claim 1, wherein the attachment deviceis located in a case which can be opened and closed and which enclosesthe release liner and electrodes prior to use, wherein closing the casecauses the attachment device to clamp the conductive layer of eachelectrode into electrical contact when the release liner is folded theone way.
 9. The release liner of claim 1, wherein the attachment deviceis located in a case which can be opened and closed and which enclosesthe release liner and electrodes prior to use, wherein closing the casecauses the attachment device to clamp the release liner with theattachment device without electrical connection between the twoelectrodes when the release liner is folded the another way.
 10. Therelease liner of claim 8, wherein the case is made of a rigid polymericmaterial.
 11. The release liner of claim 9, wherein the case is made ofa rigid polymeric material.
 12. A release liner for electrodes which maybe selectively configured to electrically connect electrodes attached tothe release liner comprising: an outer nonconductive surface to whichthe electrodes are attached; a conductor in electrical contact with eachattached electrode and nominally electrically disconnected from eachother; and a case including two covers which may be opened and closedwhich encloses the release liner and electrodes prior to use, each coverincluding a portion of a retaining device which, when the case isclosed, retains the release liner, wherein when the release liner isfolded one way the retaining device retains the electrodes in the casein an electrically connected configuration, and when the release lineris not folded the one way the retaining device retains the electrodes inthe case in an electrically disconnected configuration.
 13. The releaseliner of claim 12, wherein the conductors in electrical contact witheach attached electrode are in opposition and in contact with each otherwhen the release liner is folded the one way.
 14. The release liner ofclaim 13, wherein the retaining device comprises a spring clip.
 15. Therelease liner of claim 12, wherein the retaining device is located atthe center of the cover.
 16. The release liner of claim 12, wherein theretaining device clamps the release liner when the case is closedwithout the electrodes being located in the retaining device.
 17. Amethod for packaging a pair of electrodes attached to a release liner,the release liner including a conductor electrically connected to theelectrically conductive surface of each electrode, comprising: foldingthe release liner one way which brings the conductors into oppositionwith each other, or folding the release liner another way which does notbring the conductors into opposition with each other; and placing therelease liner and electrodes in a case having covers which may be closedto enclose the release liner and electrodes, each cover including aportion of a retaining device which retains the release liner in theretaining device when the cover is closed, wherein the retaining deviceretains the conductors in electrical contact with each other when therelease liner is folded the one way.
 18. The method of claim 17, whereinthe retaining device retains the release liner with the conductors notin electrical contact with each other when the release liner is foldedthe another way.